Flexural properties of glue-laminated bamboo

Research this study of procedure of unfolding bamboo culm, the factors and the procedures which affect the quality of glue-laminated bamboo, such as bending and shear strength. Kind of bamboo tested is the sweet bamboo, has been brought from Nongjuang District, Prachinburi. By selecting bamboo at the age of 2-3 years with the diameter is about 3-4 inches with the length of a segment is about 40-50 centimeters. In bringing divided segments and taking out the inrind and outrind to boil with hot water up to 100 degree celsius for 4 hours, then the bamboo will be unfolded flat and put into the oven continuously with the moisture content not over than 12 percent and the thin wood can be cut and shove to get 3 mm thick, and applying glue joined together with pressure 15 kg/square cm with 45 minutes application time, in order to get the specimen are 12 cm wide by 35 cm with thickness of 2 cm. And let the glue-laminated bamboo adjusted the condition of moisture content for 1 month. Then bring them to cut for testing physical and mechanical properties by using the standard of testing is B.S. 373:1957. Physical properties of glue-laminate bamboo has different values as follows. The specific gravity is 0.47-0.89, moisture content is 5.4-9.52 percent. For the flexural properties of glue-laminated bamboo has the values as follows, the paralleled glue plane has the value of flexural stress at the point P.L. 310-596 kg/square cm, modulus of rupture 601-1,379 kg/square cm, modulus of elasticity 81,287-153,638 kg/square cm, and the perpandicular glue plane, at the value of flexural stress point P.L. 210-566 kg/square cm, modulus of rupture 359-1,203 kg/square cm modulus elasticity 55,801-157,674 kg/square cm. For other quality of device with different values of glue-laminated, therefore, shear perpandicular to glue plane to 224-286 kg/square cm, shear paralleled to glue plane 54-99 kg/square cm, the horizontal shear strength at the point P.L. 16-53 kg/square cm, the ultimate horizontal shear strength 35-102 kg/square cm. In summary, bamboo can be brought to unfold flat by using heat. Heat makes bamboo soft and changing forms. The factors of unfolding bamboo which affect the age and the quantity of heat, due the age of sweet bamboo 2-3 years, and the quantity of heat over 100 degree celsius. For quality device of some joining wood made from bamboo have high values hard wood; Xylia kerrii, Dipterocarpus costatus, Pterocarpus macrocarpus, so it should be improved steps of unfolding bamboo by using higher technology, such as using compressor giving heat to the bamboo with higher temperature.